ABSTRACT
Objective:
To observe the changes of macular morphology and
blood flow after minimally invasive
vitrectomy (PPV) in
patients with severe non-proliferative
diabetic retinopathy (sNPDR).
Methods:
A prospective
clinical study. From January 2020 to April 2021, 17 consecutive sNPDR
patients with 17
eyes who were diagnosed and received PPV
treatment at the Zhongshan Ophthalmic Center of
Sun Yat-sen
University were included in the study. There were 12
males with 12
eyes and 5
females with 5
eyes; the average age was 55 years old; the average duration of diabetes was 11 years; the average
glycosylated hemoglobin was 7.9%. Before the operation and 1, 3, and 6 months after the operation, all the affected
eyes underwent best corrected
visual acuity (BCVA), standard 7-field fundus
color photography, and
optical coherence tomography angiography (OCTA). An OCTA instrument was used to scan the macular area of the affected
eye with in the range of 3 mm×3 mm to
measure the central subfoveal thickness (CST), the thickness of the
ganglion cell complex (GCC) in the macular area, the thickness of the
retinal nerve fiber layer (RNFL), and the superficial
capillary plexus (SCP) vessel density and
perfusion density in the macular area, macular avascular zone (FAZ) area, a-circularity index (AI). Before the operation and 6 months after the operation, the least significant difference test was used for the pairwise comparison.
Results:
Before the operation, 1, 3, and 6 months after the operation, the FAZ area of the macular area were 0.34±0.14, 0.35±0.10, 0.37±0.10, 0.36±0.13 mm 2, respectively; AI were 0.52±0.13, 0.54±0.11, 0.57±0.10, 0.60±0.11; CST was 282.6±66.7, 290.4±70.9, 287.2±67.5, 273.2± 49.6 μm; GCC thickness were 77.1±15.5, 74.3±13.9, 72.6±16.2, 78.5±18.3 μm; the thickness of RNFL was 97.9±13.8, 101.3±14.6, 97.7±12.0, 96.1±11.4 μm, respectively. The overall
blood flow density of SCP in the macula were (16.79±1.43)%, (16.71±1.82)%, (17.30±2.25)%, (17.35±1.22)%; the overall
perfusion density were 0.32±0.02, 0.32±0.03, 0.33±0.03, 0.33±0.02, respectively. After the operation, the CST increased first and then decreased; the thickness of RNFL increased 1 month after the operation, and then gradually decreased. Comparison of the
parameters before and 6 months after the operation showed that the AI improved, and the difference was statistically significant ( P=0.049); the difference in FAZ area and the thickness of CST, GCC, and RNFL was not statistically significant ( P=0.600, 0.694, 0.802, 0.712); There was no statistically significant difference in the
retina SCP
blood flow density and
perfusion density in the macular area ( P=0.347, 0.361).
Conclusion:
Compared with before
surgery, there is no significant change in macular structure and
blood flow density in sNPDR
patients within 6 months after minimally invasive PPV.